At the end of several weeks of work to integrate and requalify the new ambient gamma measurement channels in a controlled area in the fuel building (FB), the reactor building (RB) and the fuel transfer building (FTB), the Bertin technicians installed the first eight ionizing radiation monitoring channels at the Civaux nuclear power plant on units 1 and 2.
In addition to the monitored area, an off-line gamma measuring channel on the non-condensable gas line of the condenser (CVI) was installed in the machine room of unit 1.
A second deployment is planned for the second half of 2022 to integrate and requalify the five remaining ionizing radiation monitoring channels of the fuel, reactor and engine room buildings.
These new radiation monitoring channels are the first of a long list of equipment to be deployed until the end of 2025, which would represent a total of 24 units for the 1300 and 1400 MW series of the French nuclear power plants. Focus on the project.
The “Grand Carénage” is an important nuclear industrial programme consisting of major renovation and modernisation work aimed at extending the operating life of the French nuclear power plants. Process control and personal radiation protection, by monitoring the collective dose and reducing the individual dose, are a priority for EDF, which intends to optimize and limit exposure to ionizing radiation.
It is in this context that EDF issued an invitation to tender in 2016 to ensure the long-term and reliable operation of the ionizing radiation and monitoring channels in the reactor buildings. As part of a consortium with Clemessy and Ineo, Bertin was awarded lots 9 and 12 of this invitation to tender.
As the current supplier of radiation protection, process control and environmental monitoring systems and instruments, Bertin is responsible not only for the design, qualification, manufacture and commissioning of this new generation equipment, but also for the training of the agents and providing the associated control documentation. The objective is to:
- Modernise existing radiation monitoring channels;
- Monitor the systems currently used in the power plants, to ensure that they work properly (e.g. dissemination of radioactive elements in the environment, monitoring of the dosing processes, increasing the ambient dose rate, etc.);
- Verify the current processes to prevent any hazard for the running of the power plants, the environment and the health of the workers.
The project as a whole is broken down into 3 stages, with a study and qualification phase (completed in 2018), an equipment industrialization and production phase (in progress) and finally an installation and commissioning phase that includes the training of the EDF agents (currently in progress).
At the end of six intense years of development and qualification, Bertin will supply EDF with three types of monitoring systems to control processes and protect the operators in the fuel and reactor buildings, against radiation leaks and dispersion in particular.
- 24 Bertin GM700 CVI channels (*) (GM for Gas Monitor) for monitoring non-condensable gas leaks from the steam generator (transfer between the primary circuit and the secondary circuit of the reactor). The purpose of this equipment installed in the machine room is to continuously measure the overall gamma activity concentration of fluids in the CVI* line, by a detection system that is outside the piping and doesn’t collect any effluent samples.
- 8 Bertin GAM200 Standard FTB channels (GAM for Gamma Area Monitor) to monitor the ambient dose rate and assess the exposure to radiation of the operators in the fuel transfer buildings (FTB) during the loading and unloading of the fuel from the unit for its reprocessing, for example.
- 16 Bertin GAM200 FB-RB channels with backup (GAM for Gamma Area Monitor) for monitoring the gamma dose rate in the fuel building (FB) and the reactor building (RB). This equipment has a protected power supply unit which guarantees a backup power supply of 8 hours during operation, apart from the mains power supply. In the case of the RB and the FB, the channels are installed in pairs, one on the wall which monitors the pool (redundant channel), and the other on the mobile walkway which manages the movement of the fuel in the pool. The purpose of these fixed channels are to monitor the fuel transfer process and protect the operators in the reactor building as a result. Indeed, they can detect the significant increase in the dose rate in the installation, including if some fuel gets blocked or in other situations.
To date, Bertin’s service teams have completed the installation of the channels of the Civaux power plant unit 1 and started to install the channels of unit 2 according to a schedule defined with EDF. The rest of the installation of unit 2 will continue from the second half of 2022.
Of all of the teams working across France, Bertin has set up a team of coordinators in order to fulfil EDF’s need to requalify the on-site monitoring channels and to train the operators. On-site training is then provided to the EDF agents following the re-qualification of the channels. This training course is used to pass on the elements needed to ensure that this new equipment works properly.
Since 2017, Bertin has also maintained the operational conditions of the existing ionizing radiation channels on 14 EDF units. This allowed Bertin to acquire and master perfectly the specific operating and intervention constraints of the radiation monitoring channels.
As part of a complementary contract with the UFPI (Unité de professionnalisation pour la Performance Industrielle – Professionalisation Unit for Industrial Performance), Bertin has set up a training unit made up of two coordinators on Thiron-Gardais production site. Two types of non-qualifying training courses are thereby given to NPP Auto service agents who are in charge of operating GM700 and GAM200 monitors, and, more generally, EDF’s radiation monitoring channels.
Entering the market for qualified control monitoring equipment important for nuclear safety is therefore a major step forwards for Bertin, as it confirms its high degree of expertise in the nuclear instrumentation sector, for which it continues to innovate.
FB RB**: fuel building; reactor building
CVI: vacuum circuit, which is designed to remove the non-condensible gases polluted by radioactive gases from the condenser which are released into the atmosphere through the NAB chimney after being verified and counted.
NAB: Nuclear Auxiliary Building